“Cosmus, Duke of Florence, was wont to say of perfidious friends, that "We read that we ought to forgive our enemies; but we do not read that we ought to forgive our friends."”

As quoted in Diogenes Laërtius, Lives and Opinions of Eminent Philosophers, "Pythagoras", Sect. 23, as translated in Dictionary of Quotations http://archive.org/details/dictionaryquota02harbgoog (1906) by Thomas Benfield Harbottle, p. 320

Nana (1880).

Aristotle, 9.
The Lives and Opinions of Eminent Philosophers (c. 200 A.D.), Book 5: The Peripatetics

Source: 1800s, Jerusalem The Emanation of The Giant Albion (c. 1803–1820), Ch. 4, plate 91, line 1

Source: How To Write A Sentence And How To Read One (2011), Chapter 1, Why Sentences?, p. 4

1950s, Loving Your Enemies (Christmas 1957)
Context: Forgiveness does not mean ignoring what has been done or putting a false label on an evil act. It means, rather, that the evil act no longer remains as a barrier to the relationship. Forgiveness is a catalyst creating the atmosphere necessary for a fresh start and a new beginning. It is the lifting of a burden or the canceling of a debt. The words "I will forgive you, but never forget what you have done" never explain the real nature of forgiveness. Certainly one can never forget, if that means erasing totally for his mind. But when we forgive, we forget in the sense that the evil deed is no longer a mental block impeding a new relationship. Likewise, we can never say, "I will forgive you, but I won't have anything further to do with you." Forgiveness means reconciliation, a coming together again. Without this, no man can ever love his enemies. The degree to which we are able to forgive determines the degree to which we are able to love our enemies.

Chap. 1: "To Whom Much is Forgiven..."
The New Being (1955)

Wir sollen immer verzeihen, dem Reuigen um seinetwillen, dem Reuelosen um unseretwillen.
Source: Aphorisms (1880/1893), p. 25.